Assig-nob of one-half



(NoModl.)

El. T. STARR. EEEGTRODE EOE ELECTRIC BATTERIES.

. No. 290,941. Patented 1360.251883.

N. PETERS. Phomnumgmpncr. wmhmgm". D. C.

I5 Y give off electric currents or energy uponconnecting their electrodes by a conductor.

Y, To all whom, it may concern:

UNITED STATESPATENT OFFICE.

ELI T. STARR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALF A TO H. M. LEVIS AND JAMES W. WHITE, BOTH OF SAME PLACE, AND

. VILLIAM J'. PEYTON, OF VASHINGTON, DISTRICT OF COLUMBIA.

ECTRIC BATTERIES.

l SPECIFICATION forming part of Letters Patent No. 290,941, dated December 25, 1888.

Application mea oeiotr 2o, issn. (No moaei.)

y Be it known that I, ELI T. STARR, of the city and county of Philadelphia,in the State of Pennsylvania, have invented certain new and I useful Improvements in Electrodes for Elec-i tric Batteries, of `which the following is a speciiication.

My invention relates more particularly tof' electrodes or elements .for electric batteries? ofthe class commonly known as secondary or storage batteries. Thesebatteries generatel no electricity of themselves, but when sub-l mitted to the action of an electric current from l a suitable generator passing through them they become charged or put into condition to The object of my invention more particu-i larly is to improve secondary-battery elements vby giving them large active surface withini comparatively small space an d with diminished weight, and, further, to cheapen the cost and;

Ysimplify the manufacture of the elements.

IheV subject-matter claimed is particularly i pointed out at the close of the specioation.

In order to carry my improved method of constructing secondarylbattery elements into effect, and to produce an improved electrode or element constructed according to my invention, I take nely-divided lead-such as thinlead shavings or particles-and either mix it with oxide of lead or coat the lead parti- .cles superiicially. with oxide by submitting them, for instance, to the action of an electric current 1n well-known ways. This `finely-divided lead, or lead particles and oxide, con- .stitutes the active. and also the electro-conducting portions of the element. It is to be understood, however, that other nely-divided active material suitable for secondary batteries may be employed instead of the lead and oxide-for instance, the oxide or the peroxide alone; but the claim which I make herein at the close of the specification is intentionally and definitely limited to lead or a lead compound as the activeinaterial of the element, as I have found, after much study and experiment, that lead or a lead compound is peculiarly and particularly efficient and desirable in connection with a non-active binding agent, 5o as described by 1ne,when used as a secondary element.

Theactive material is thoroughly mixed with a proper proportion (hereinafter indicated) of some non-active binding material- 5 5 such as shellac, beeswax, rosin, sulphur, or some such similar non-active material-which requires the action of heat or of a solvent to convert it intol a soft or liquid form, and which upon cooling or'evaporation or volatilization 6o vof the solvent becomes set7 or hard, so as to be self-sustaining as a mass. The non-active material is used solely as a binding agent f for the active material, so as to enable the .finely-divided active material to be converted 65 into a porous self-sustaining mass, presenting an electro-conducting body having large active surface, such extent of surface being requisite for accumulating a large amount of energy. Aplain plate or sheet of lead or 7o v other metal as a secondary-battery element is practically defective, in that its surface, which is chemically affected, is limited in proportion to its weight; hence the utility of providing an element of comparatively small weight and 7 5 compass with large active surface or surfaces to be chemically affected under the action of an electric current traversing an electrolytic fluid in the battery-cell. The proportion of the active material to the non-active binding So material will generally be about in the ratio of two-thirds, in bulk, of active material to onethird of binding material; but the proportion of the active material to the non-active .or binding materiallnay be widely varied, while 85 still affording good results. The proportion, however, of the active material should always be sufficient to allow of the active particles being in contact throughout the mass, as the area of conductivity of the element will be 9o dependent upon such contact ofthe electro-conducting active particles.

The active material may be mechanically mixed with the non-active binding material prior to bringing the latter to a plastic orI g5 fluid form. Upon submitting such a mixture to the action of heat, when necessary, in convertin g the non-active material to a fiuid form, the active material will be so encompassed and bound throughout its mass by the fluid material that upon cooling and setting-or hardening said non-active material will bind the active material into a self-supporting mass suitable for a secondary-battery element. Ou the other hand, the non-active binding mate rial may be rst brought to a iluid state by heat or by a solvent and then have the active material thoroughly mixed or incorporated with it, and in such ease the mixture will become set or hard upon cooling, or, in case a solvent is used, upon the evaporation or volatilization of the solvent. In either case, when heat is used, before the conglomerated mass has cooled, I place the mass, orso much thereof as may be required to make an element, in a mold of the desired form and subject it to pressure sufficient to compact it and make it conform to the shape required. The mass, upon cooling, is removed from the mold, and will be found to be a firmly-coherent self-sustaining body, the active material being firmly bound together by the non-active binding material of the mass. After the electrode has been constructed, the non-active binding material is cut out of or removed from the surface of the element by an appropriate solvent that will not affect the active material. If, for instance, the finely-divided active material has been bound together by gum-shellac, the shellac on the surface of the element may be cut out or removed with alcohol or with ahot solution of soda-water, and thereby a large surface of the active material will be exposed to be affected by the electrolytic action of the charging-current, by which the battery is put into condition to give forth electric energy.

rIhe binding agent is preferably a material insoluble in water or dilute sulphuric acid, or, in other words, in the usual fluid of abattery-cell; and in the construction of my improved electrodes preferably only the binding agent at the surface of the electrodes is removed, as above indicated, to more thoroughly expose the active particles, and consequently a large active surface. In some cases, however, the soluble binding agent need not be wholly insoluble in the fluid of the battery, because upon repeatedly charging and discharging the electrodes in the process of forming and in using them the active material acquires the property of holding itselt together, or, in other words, becomes set or sel f-sus taining to a large degree.

In molding the electrodes, they are preferably provided with a large number of holes or openings extending through them from side to side, for the free circulation of the eleetrolytic fluid of the cell, and for the more 'ready action of the accumulating forces upon the element.

Ihave thus described the best ways now known to me of constructing asecondary-battery element of a mixture of finely-divided active material with a non-aeti ve binding material, which acts to bind the active material into a iirmlycoherent self-sustaining body when the non-active binding material cools or sets and hardcns after being brought to a fluid condition by the action of heat or of a solvent.

The condacting-connection of my improved electrode may be made by drilling a hole in the mass at one or more of its edges. The effeet ofthe drilling is to stretch the lead particles acted upon by the drill, and close or substantially close the interstices which may exist between them, whereby a continuous lead or metallic conduct-ingsurfacc is provided for the connection. rI'he conducting-connection-a wire, for instance-is placed in the hole or holes thus drilled, and is locked therein A by pack in g the opening around the wire with au amalgam-for instance, such as an amalgam of silver, lead, and mercury-aud also by packing the amalgam into holes which may be formed in the electrode to intersect that in which the connecting-wire is inserted. A perfect contact of the conducting-wire with the electrode is thus provided bythe amalgam connect-ion, which is a better conductor than the electrode, and oxidizing of the joints between the surfaces of the electrode and connection is effectually prevented.

In the accompanying drawings, at Fig. l I have shown one of my improved electrodes with Va series ot' holes extending through it, the amalgam connection a between the electrode and its conducting-wire Z1 being also shown, and at Fig. 2 I have shown a sectional view through the electrode shown in Fig. l. I have shown the electrode of circular or disk form, but of' course it will be understood that the shape is immaterial, a flat rectangular plate being desirable in some instances.

I mean by non-active binding agent,77 as used in this specification, a binding agentwhich is not chemically affected bythe charging of the battery, the metallic matter heilig for that purpose.

I reserve the right hereafter to file an application or applications for allthe patentable subject-matter disclosed in this patent, not specifically claimed herein, and this reservation is in no wise affected by the making and erasing of claims during the pendency of the application upon which this patent was granted. The matter claimed and erased is reserved as subject-matter for future applieation, as well as that which was not particularly claimed.

The subject-matter claimed in this present case is limited to that particularly recited in the following claim; and I here disclaim in favor of my prior application tiled July 24, 1882, any and all patcntable subject-matter common to said application and this present case which is not specifically claimed herein.

I may add that the process described herein ICO IIO

291mm l s of constructing battery-electrodes, consisting in mixing jiinely-divided active material with a. non-activebinding agent brought to a fluid or plastic condition by the action of heat, molding the mixture into shape before it cools or hardens, and hardening the mixture by cooling to bind the active matter together to form an electrode having active particles eX- posed to the battery-fluid, together with the process set forth which involves the further step of molding the mixture under articial pressure, is or are claimed by me in an application led December 5, 1883, as a division of this presentl case, such division being filed upon the demand of the Patent Office to that 15 effect. y 

